From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8BAB8C2D0DB for ; Fri, 24 Jan 2020 11:02:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 630C32087E for ; Fri, 24 Jan 2020 11:02:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579863778; bh=fy19I0vOwJrBMY/7U50STJKg69HUaZHsyoy2OiGgDaA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=WF1vrvxHs1/BgGA6ZUEYafveQnNivZ8uHqz6xOB/J4xkBp//RJPNcLgF22WUvOvRI +EoVOPSUCi249i/06Hyd/uNwIl+m3HfwjIjmCfyXDDLcbhBGMcMgztAiwR1FIs5Nmd +M+EwDS5V52G9wscX+wojQ74iW6SfFrx0Dmosb08= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388215AbgAXLC5 (ORCPT ); Fri, 24 Jan 2020 06:02:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:36596 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732881AbgAXLC4 (ORCPT ); Fri, 24 Jan 2020 06:02:56 -0500 Received: from localhost (ip-213-127-102-57.ip.prioritytelecom.net [213.127.102.57]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6FFA92071A; Fri, 24 Jan 2020 11:02:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579863776; bh=fy19I0vOwJrBMY/7U50STJKg69HUaZHsyoy2OiGgDaA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aEHmf4CuRL04S0ayblWujW0V17KZxV97yKONUaPgfODO/shPobPdJyPoxwhOnVh6a FZsi5qAq22EnZp1SnscKq2pHkjkW10fzbmvfjkXKgV1htbMuEroQTw6x/TVmclAr4S 8/m/AxAuQbMXcDA7kg8sHTZwHhXJznDDZc5TsJCM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Willem de Bruijn , "David S. Miller" , Sasha Levin Subject: [PATCH 4.19 072/639] net: always initialize pagedlen Date: Fri, 24 Jan 2020 10:24:02 +0100 Message-Id: <20200124093056.417796600@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200124093047.008739095@linuxfoundation.org> References: <20200124093047.008739095@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Willem de Bruijn [ Upstream commit aba36930a35e7f1fe1319b203f25c05d6c119936 ] In ip packet generation, pagedlen is initialized for each skb at the start of the loop in __ip(6)_append_data, before label alloc_new_skb. Depending on compiler options, code can be generated that jumps to this label, triggering use of an an uninitialized variable. In practice, at -O2, the generated code moves the initialization below the label. But the code should not rely on that for correctness. Fixes: 15e36f5b8e98 ("udp: paged allocation with gso") Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/ip_output.c | 3 ++- net/ipv6/ip6_output.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index d63091812342f..fbf30122e8bf2 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -940,7 +940,7 @@ static int __ip_append_data(struct sock *sk, unsigned int fraglen; unsigned int fraggap; unsigned int alloclen; - unsigned int pagedlen = 0; + unsigned int pagedlen; struct sk_buff *skb_prev; alloc_new_skb: skb_prev = skb; @@ -957,6 +957,7 @@ alloc_new_skb: if (datalen > mtu - fragheaderlen) datalen = maxfraglen - fragheaderlen; fraglen = datalen + fragheaderlen; + pagedlen = 0; if ((flags & MSG_MORE) && !(rt->dst.dev->features&NETIF_F_SG)) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index eed9231c90ad5..9886a84c25117 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1357,7 +1357,7 @@ emsgsize: unsigned int fraglen; unsigned int fraggap; unsigned int alloclen; - unsigned int pagedlen = 0; + unsigned int pagedlen; alloc_new_skb: /* There's no room in the current skb */ if (skb) @@ -1381,6 +1381,7 @@ alloc_new_skb: if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len; fraglen = datalen + fragheaderlen; + pagedlen = 0; if ((flags & MSG_MORE) && !(rt->dst.dev->features&NETIF_F_SG)) -- 2.20.1